⬆️ Bump golang in /docker/production

Bumps golang from 1.21.2-alpine to 1.21.3-alpine.

---
updated-dependencies:
- dependency-name: golang
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>

docker/production/Dockerfile

@@ -1,6 +1,6 @@
 # syntax = docker/dockerfile:1
 
-FROM golang:1.21.2-alpine AS build
+FROM golang:1.21.3-alpine AS build
 
 RUN apk add --update --no-cache git